The vessel cleaning system is designed for removing an obstruction from within a patient's vessel through a tube of small diameter and particularly for opening vessels, such as blood vessels, that tend to become obstructed by a thrombus.
Current treatments such as pharmacological, surgical or trans-catheter procedures can be time-consuming, traumatic and expensive. Thus, objects of the present invention are to simplify, improve and shorten the procedure by enabling the physician to navigate and advance the system through obstructions, curved vessels and bifurcations and then break the obstruction into small pieces that can be removed through a tube by suction and by mechanical means. To further reduce the likelihood that the pieces of the obstruction are carried downstream into the vasculature, the system can be delivered and guided through a catheter with an inflatable distal barrier so that the flow through the vessel can be temporarily occluded during the procedure.
The system comprises a housing that is connected to a flexible-tube, a motor-driven flexible agitator-shaft that is rotatably disposed in the flexible-tube, and an offset distal-agitator connected to the agitator-shaft. The distal-agitator extends out of the open distal end of the flexible-tube to break the obstruction into pieces while rotating with an effective diameter that is larger than its cross-sectional diameter.
The distal-agitator is preferably made of a flattened wire wound on its flat side to form a spiral. A distal-tip of the distal-agitator is rounded to minimize trauma to the vessel's wall. The distal-tip is preferably formed by melting the spiral wire and allowing it to re-solidify.
The direction of the winding relative to the direction of rotation of the distal-agitator is chosen so that it automatically unscrews from tight engagements with its surroundings similarly to a corkscrew releasing itself from engagement with a cork.
The agitator-shaft can be made, at least partially, of a spiral wire that is preferably a continuation of the wire from which the distal-agitator is made of. A spacing between coils of the spiral wire make the agitator-shaft longitudinally compressible so that the distal-agitator can retract into the flexible-tube when it unscrews itself from a tight engagement with its surroundings. Further, in response to an elevated torque that the agitator-shaft transmits, to unscrew the distal-agitator from the tight engagement, the agitator-shaft tends to contract both diametrically and longitudinally, thereby pulling the distal-agitator into the flexible-tube.
While the agitator-shaft is preferably made to be able to contract longitudinally, the extent it can expand longitudinally can be limited by adding a central tension member that is connected to the proximal and distal ends of the agitator-shaft.
The distal-agitator is a short flexible curved section that extends out the flexible tube and is asymmetrically offset to only one side of the longitudinal axis of the agitator-shaft. Upon encountering a hard or tight spot in the obstructed vessel such asymmetrical construction is able to rotate around a shifted axis with a decreased effective diameter so that it can be rotated with less torque as compared with a symmetrical distal agitator (it can be appreciated that if the offset was symmetrical, the shifting of the axis would not decrease the effective diameter).
It also can be appreciated that since the distal-agitator is flexible, the offset can decrease due to a reaction force applied to it by the vessel's wall or, it can dynamically increase due to centrifugal force acting on its asymmetrical structure.
The agitator-shaft radially supports the flexible-tube in which it rotates while the system is operated in curved vessels.
The system is inserted into the vessel directly (e.g., when access to the vessel is gained surgically) or through an introducer. The introducer comprises a first side port that can be utilized to either inject or aspirate fluids and particles into or from the vessel.
Optionally, a catheter can be used to guide the system into the vessel. Such catheter can comprise a toroidal barrier at its distal end section for temporarily blocking flow between the catheter and the vessel. This allows the system to macerate and remove the obstructing material while avoiding release of obstruction particles downstream.
A passageway, defined through the system's housing, connects the flexible-tube with an external port so that the port can be utilized to inject or aspirate fluids and particles into or from the vessel, respectively.
The agitator-shaft is mechanically connected to an output shaft of the motor by a coupling. The coupling is made of an insolating material that minimizes electrical and electromagnetic energy transfer from the motor output shaft through the agitator-shaft to the patient and the surroundings.
The motor has a casing, at least a portion of which is made of conductive material, e.g., of metal. The motor is connected to a first wire and a second wire that supply electrical power to cause the motor's output shaft to rotate. To minimize the generation and emission of electromagnetic energy, a first capacitance is interposed between the portion of the motor's casing that is made of conductive material and the first wire, a second capacitance is interposed between the portion of the casing that is made of conductive material and the second wire, and a third capacitance is interposed between the first and the second wires.
To prevent the flexible-tube from kinking (i.e., diametrically collapsing) and to prevent the agitator-shaft from being sharply bent at the point in which they are connected to the housing, their radius of bending is limited to a radius of curvature of a wall of a depression defined by the housing that surrounds the tubes. Optionally, the depression can be formed in a separate block that is pressed into the housing, after the outer tube has been bonded to the housing, to reduce the likelihood of any residue of the bonding process deforming the curvature defined by the radius of the wall.
The system can be manufactured in varying lengths and diameters to reach and treat different locations in the human anatomy and different conditions of occlusive diseases, as well as to suit variations in the methods of use and physicians' preferences of operating the device.
To remove an obstruction from within a patient's vessel, a system, according to the present invention, is advanced into the vessel and the motor is activated to rotate the agitator-shaft, which in turn rotates the distal-agitator, breaking the obstruction to pieces. As the distal-agitator is rotated at the speed that is sufficient to break the obstruction to pieces, the centrifugal force acting on the asymmetrical distal-agitator tends to increase its effective diameter by elastically deforming it.
The system can be inserted into the vessel directly (e.g., when used intraoperatively where direct access to the vessel is gained surgically), or percutaneously through an introducer or through a catheter especially when using a long system, e.g., a system that is introduced through the skin at the groin area and is guided from the groin area with a catheter to vessels serving the heart or brain.